| 1 | Ronald Myers Inc. | 387 | 1,637 | 3,060 |
| 2 | Mobile Environmental Analytical Inc. | 277 | 286 | 849 |
| 3 | Odyssey Environmental Services, Inc. | 214 | 413 | 7,584 |
| 4 | Eichelbergers Inc. | 186 | 686 | 37,074 |
| 5 | Parratt-Wolff Inc. | 88 | 146 | 3,500 |
| 6 | Duane Moyer Well Drilling | 68 | 215 | 11,486 |
| 7 | Negley's Well Drilling, LLC | 61 | 61 | 9,098 |
| 8 | Labella Environmental, LLC | 60 | 61 | 253 |
| 9 | Summit Drilling LLC | 40 | 50 | 1,492 |
| 10 | C S Garber & Sons Inc. | 37 | 114 | 18,484 |
| 11 | Greg Sorber Well Drilling, LLC | 37 | 77 | 127 |
| 12 | Ameridrill, Inc. | 35 | 89 | 5,442 |
| 13 | East Coast Drilling, Inc. | 30 | 30 | 1,106 |
| 14 | Leidos | 21 | 50 | 338 |
| 15 | Bellview Pump, LLC | 21 | 34 | 1,025 |
| 16 | Swank & Son Pump Co., Inc. | 18 | 60 | 1,985 |
| 17 | Cresswell Drilling Co. Inc. | 17 | 24 | 1,525 |
| 18 | Knight Well Drilling Inc. | 16 | 65 | 9,484 |
| 19 | Jack Ziegler Well Drilling Inc. | 14 | 29 | 5,789 |
| 20 | Bell Bros Well Drl & Water Sys Solns | 12 | 39 | 2,190 |
| 21 | Stackhouse & Son Inc. | 10 | 56 | 881 |
| 22 | George Leib Well Drilling Inc. | 9 | 177 | 908 |
| 23 | Environmental Probing Investigations Inc. | 9 | 9 | 1,212 |
| 24 | Allied Well Drilling | 8 | 71 | 2,213 |
| 25 | Van Fleet Drilling Company Inc. | 8 | 16 | 1,324 |
| 26 | Kocher's Water Pumps & Tanks Inc. | 8 | 15 | 2,402 |
| 27 | Drake Well Drilling, Inc. | 7 | 20 | 2,621 |
| 28 | Tyler Pump And Well Services, LLC | 7 | 7 | 317 |
| 29 | Williams Well Drilling | 6 | 6 | 514 |
| 30 | Talon Drilling Company | 4 | 44 | 1,966 |
| 31 | Environmental Field Service Inc. | 4 | 4 | 74 |
| 32 | Fritz Bros Inc. | 3 | 7 | 1,424 |
| 33 | Morrison Excavating Morrison Excavating Inc. | 3 | 5 | 1,160 |
| 34 | Active Environmental Technologies, Inc. | 3 | 3 | 206 |
| 35 | Advanced Drilling Inc. | 2 | 9 | 248 |
| 36 | Rumsey Well Drilling LLC | 2 | 7 | 1,974 |
| 37 | Marti Cascade | 2 | 2 | 342 |
| 38 | Werner & Sons Well Drilling LLC | 1 | 3 | 1,396 |
| 39 | G S Fleese Drillin | 1 | 3 | 248 |
| 40 | Todd Mayer's Well Drilling | 1 | 2 | 5,307 |
| 41 | Kibler Well Drilling LLC | 1 | 2 | 3,255 |
| 42 | Edward Hook Hook Well Drilling Inc. | 1 | 1 | 471 |
| 43 | Patrick Ferris Company LLC | 1 | 1 | 27 |
| 44 | Robert J Shelhamer | — | 552 | 820 |
| 45 | Myers Drilling Inc. | — | 353 | 3,404 |
| 46 | B. L. Myers Bros OF MD,LLC | — | 124 | 12,524 |
| 47 | Fenstemaker & Sons Well Drilling | — | 114 | 547 |
| 48 | Champion Drilling | — | 102 | 514 |
| 49 | Paul's Well Drilling | — | 65 | 101 |
| 50 | Phares Fry Well Drilling & Pump Svc Inc. | — | 58 | 5,909 |
| 51 | Stanley Thomas Well Drilling | — | 49 | 607 |
| 52 | Carl L Kresge & Sons Inc. | — | 49 | 257 |
| 53 | Raymond E Kresge | — | 40 | 104 |
| 54 | Aquadrill Inc. | — | 40 | 40 |
| 55 | Alfred Dailey | — | 35 | 41 |
| 56 | Christopher Kasa / Casey-Kassa Drilling Co. | — | 32 | 350 |
| 57 | R R Hornberger | — | 29 | 508 |
| 58 | Albert Myers | — | 27 | 31 |
| 59 | New Way Drilling II Inc. | — | 25 | 3,892 |
| 60 | Old Way Drilling Co. | — | 25 | 705 |
| 61 | Randler's Well Drilling Inc. | — | 23 | 1,121 |
| 62 | Shelhamer Sons Inc. | — | 20 | 26 |
| 63 | Austin James Associates, Inc. | — | 19 | 217 |
| 64 | Myers Brothers Drilling Contr.,Inc. | — | 17 | 33,477 |
| 65 | Pennsylvania Tectonics, Inc. | — | 17 | 207 |
| 66 | Clifton Buck | — | 13 | 157 |
| 67 | Water Well Drillers Licensing--Topo Geo | — | 12 | 732 |
| 68 | Charles D Moyer | — | 9 | 940 |
| 69 | Andrew S Mermon | — | 8 | 756 |
| 70 | Leonard M. Borger Inc. | — | 5 | 2,160 |
| 71 | Martin Schafer Jr. Inc. Well Drilling | — | 5 | 593 |
| 72 | Virgil Buck | — | 5 | 59 |
| 73 | Geo-Environmental Drilling Co. Inc. | — | 4 | 3,228 |
| 74 | Dogan Well Drilling Inc. | — | 4 | 1,731 |
| 75 | Tully Drilling Co. Inc. | — | 4 | 1,139 |
| 76 | Chasity Jones | — | 4 | 214 |
| 77 | Terra Testing, Inc. | — | 3 | 4,532 |
| 78 | Shiffer Drilling, Inc. | — | 3 | 904 |
| 79 | Sensenig & Weaver Well Drilling Inc. | — | 2 | 18,480 |
| 80 | Allen H Dorn | — | 2 | 1,787 |
| 81 | Gill Enterprises Inc. | — | 2 | 449 |
| 82 | J Karp & Sons, Inc. | — | 2 | 397 |
| 83 | Arnold Drilling LLC | — | 2 | 266 |
| 84 | Alexander's | — | 1 | 3,447 |
| 85 | R H Odenheimer Co. | — | 1 | 5,276 |
| 86 | Mayer's Well Drilling | — | 1 | 2,948 |
| 87 | Moody And Associates, Inc. | — | 1 | 1,117 |
| 88 | Wilson Electric Pumps Inc. | — | 1 | 5,745 |
| 89 | Harrisburg's Kohl Bros Inc. | — | 1 | 2,819 |
| 90 | Kohl Bros., Inc. | — | 1 | 2,398 |
| 91 | Snyder Well Drilling Inc. | — | 1 | 1,464 |
| 92 | Reith Bros. Inc. | — | 1 | 1,435 |
| 93 | Wieand Brothers Well Drilling Inc. | — | 1 | 1,198 |
| 94 | Gower Well Drilling And Pump Service Inc. | — | 1 | 1,132 |
| 95 | Lutz Environmental Co., Inc. | — | 1 | 431 |
| 96 | Mummert & Sterner | — | 1 | 301 |
| 97 | Raymond E Werner | — | 1 | 195 |
| 98 | Roy Zimmerman | — | 1 | 173 |
| 99 | Reith Geothermal Energy Inc. | — | 1 | 153 |
| 100 | George Turner | — | 1 | 72 |
| 101 | Chrin OF Delaware, Inc. | — | 1 | 62 |
| 102 | Leroy Titman And Frank Stackhouse | — | 1 | 57 |
| 103 | Layne Christensen Company | — | 1 | 44 |
| 104 | William O Young | — | 1 | 37 |
| 105 | Sprague & Henwood Inc. | — | 1 | 25 |